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Diffstat (limited to 'fs/nfsd/nfsxdr.c')
-rw-r--r--fs/nfsd/nfsxdr.c46
1 files changed, 39 insertions, 7 deletions
diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index 0c24b9e24fe8..6035e03655c6 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -284,8 +284,9 @@ int
nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p,
struct nfsd_writeargs *args)
{
- unsigned int len;
+ unsigned int len, hdr, dlen;
int v;
+
if (!(p = decode_fh(p, &args->fh)))
return 0;
@@ -293,11 +294,42 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p,
args->offset = ntohl(*p++); /* offset */
p++; /* totalcount */
len = args->len = ntohl(*p++);
- rqstp->rq_vec[0].iov_base = (void*)p;
- rqstp->rq_vec[0].iov_len = rqstp->rq_arg.head[0].iov_len -
- (((void*)p) - rqstp->rq_arg.head[0].iov_base);
+ /*
+ * The protocol specifies a maximum of 8192 bytes.
+ */
if (len > NFSSVC_MAXBLKSIZE_V2)
- len = NFSSVC_MAXBLKSIZE_V2;
+ return 0;
+
+ /*
+ * Check to make sure that we got the right number of
+ * bytes.
+ *
+ * If more than one page was used, then compute the length
+ * of the data in the request as the total size of the
+ * request minus the transport protocol headers minus the
+ * RPC protocol headers minus the NFS protocol fields
+ * already consumed. If the request fits into a single
+ * page, then compete the length of the data as the size
+ * of the NFS portion of the request minus the NFS
+ * protocol fields already consumed.
+ */
+ hdr = (void*)p - rqstp->rq_arg.head[0].iov_base;
+ if (rqstp->rq_respages != rqstp->rq_pages + 1) {
+ dlen = rqstp->rq_arg.len -
+ (PAGE_SIZE - rqstp->rq_arg.head[0].iov_len) - hdr;
+ } else {
+ dlen = rqstp->rq_arg.head[0].iov_len - hdr;
+ }
+ /*
+ * Round the length of the data which was specified up to
+ * the next multiple of XDR units and then compare that
+ * against the length which was actually received.
+ */
+ if (dlen != ((len + 3) & ~0x3))
+ return 0;
+
+ rqstp->rq_vec[0].iov_base = (void*)p;
+ rqstp->rq_vec[0].iov_len = rqstp->rq_arg.head[0].iov_len - hdr;
v = 0;
while (len > rqstp->rq_vec[v].iov_len) {
len -= rqstp->rq_vec[v].iov_len;
@@ -306,8 +338,8 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p,
rqstp->rq_vec[v].iov_len = PAGE_SIZE;
}
rqstp->rq_vec[v].iov_len = len;
- args->vlen = v+1;
- return rqstp->rq_vec[0].iov_len > 0;
+ args->vlen = v + 1;
+ return 1;
}
int